Such a flow adjustment valve is, for example, known from WO 01/71289 A1.
In liquid-filled systems, such as heating and refrigeration systems, such a flow adjustment valve is used to set a hydraulic balance between different sections of the system. For this purpose, the throttle unit is set so that with given pressure conditions a certain flow through the flow adjustment valve can take place. This flow is then the flow that is allocated to the corresponding section of the system. Usually, such a flow adjustment valve is provided with two pressure measuring outputs, by means of which a pressure difference across a throttle can be determined, this pressure difference again being convertible into a flow. The throttle can be a constant throttle. However, it is also possible to use the throttle unit as throttle. In this case, additionally to the pressure difference, information about the position of the throttle element or the opening width of the throttle unit is required.
In many cases, however, the flow adjustment valve is also used as shut-off valve, to enable shutting off the corresponding section of the system, if maintenance work is required.
With the flow adjustment valve known from WO 01/71289 A1, the shut-off element that is formed as a ball, can be rotated by means of a handle to a closed position, in which it blocks the flow channel, or to an open position, in which a passage through the shut-off element is brought to overlap the flow channel.
The handle has an opening, through which a tool can be inserted, by means of which the throttle element can be set.
When, once, such a flow adjustment valve has been set, a further setting will usually not be required. Changes of the setting usually only occur in connection with changes in the system. For this reason, such a flow adjustment valve is often located in inaccessible positions, for example in a canal, under a roof, or the like. However, this location makes it difficult for an installer to reach the flow adjustment valve.